1. Field of the Invention
This invention relates to a restoration anchoring system for cavity walls, and, more particularly to an anchoring system that remedies the fault that has occurred and constructs a repaired wall that withstands seismic and high-wind load conditions. The anchoring system includes a novel restoration seismic clip.
2. Background of the Prior Art
The construction of cavity walls consisting of an inner wythe or backup wall and an outer wythe or veneer is well known. During construction, the inner and outer portions are tied together by anchoring systems governed by local customs and building codes, which systems are designed to ensure structural integrity and to resist destructive forces.
The inventors' patents and their assignee's product line include masonry accessories, namely, ladder and truss reinforcements, wall anchors, veneer ties, masonry flashing and related items for cavity walls. These products, which are sold under the trademarks of Lox All, DW-10X, X-seal and FlexFlash, are manufactured by Hohmann & Barnard, Inc., Hauppauge, N.Y. 11788 (“H&B”), a unit of MiTek Industries, Inc., a Berkshire Hathaway subsidiary. The products have become widely accepted in the construction industry and the inventors have gained particular insight into the technological needs of this marketplace.
From time-to-time or with the passage of time, cavity walls have been known to experience levels of instability requiring remediation. Instability may result from any of a number of causes, namely, inter alia: including improper installation of the original anchoring system; the corrosion of imbedded reinforcing steel, a seismic event; settlement of the building, unanticipated differences in thermal expansion; and, historic high-wind shear conditions. Such instability results in masonry veneer cracking and spalling, the most frequent cause of masonry performance failure and potentially dangerous to the building occupants and pedestrians.
Cracking and spalling requires remediation or restabilization of the veneer by opting to: (1) remove and replace the veneer; (2) remove and re-anchor partial or selective veneer sections; or, (3) re-anchor or mechanically retie the veneer to the inner wythe. Among these options typically complete removal of a veneer and subsequent replacement is impractical and expensive. Similarly, the partial removal of sections or stories of veneer is unsafe and costly. Thus, the third option of adding or replacing mechanical anchoring as the most practical, least invasive and most cost effective repair technique.
The remediation of a failed structure is in many ways more difficult than forming the original construct. This is especially the case with cavity walls as the operating space—the bed joint of the veneer—is already enclosed. In most cavity walls, the veneer bed joint is 0.375 inch in height and within this height the replacement anchoring needs to be embedded. In order to re-anchor the veneer, the mason must work within the bed joint space and carefully clear away just enough mortar to provide a space for installation of the new tie system without structurally damaging the veneer.
In the past, the cracking of masonry structures has received extensive attention both in academic and specifically in architectural engineering publications. Noteworthy among studies is the work of Clayford T. Grimm entitled Masonry Cracks: A review of the literature (Special Technical Publications 992, 1998; American Society of Testing and Materials, Phila, Pa. 19103 pp. 257-276).
The use of helical dowels or wall ties is the most cost-effective and least invasive way of retrofitting a connection between the veneer and the inner wythe of a building. The helical wall tie is either self-drilling, self-tapping or is installed into a pre-drilled pilot hole and cuts its own thread to form a flexible threaded connection between the veneer and the inner wythe. The helical form acts as a spring to absorb differential movement without inducing cracking. Once installed, the helical anchors resist veneer loading in both compression and tension. The helix of the helical dowel minimizes retention of water in the cavity by forming and releasing droplets of water to the masonry flashing portion.
Although not provided as a seismic system, the application of helical dowels to anchoring systems was disclosed in the European Patent Applications 015906 A2, filed Jan. 4, 1985, and 0171250 A2, filed Jul. 29, 1985 of William J. B. Ollis and William H. Ollis. The Ollis et al. patent applications describe emplacing a helical dowel into an undersized pilot hole and upon hammering, causing the helical fin to rotatingly cut into the pilot hole wall. Later, the inventors commercialized their product in the United Kingdom through the Heli-Fix Corporation.
While the Ollis helical dowel serves to reconnect the veneer to the inner wythe, it fails to provide a connection to a reinforcement wire that is set within the horizontal bed joint to form a seismic construct. The present invention discloses a novel system that employs a three piece novel reconstruction wall tie system. The novel system includes a helical wall tie, T-clip and reinforcement wire. The helical wall tie is installed using a hammer drill and secures the veneer to the inner wythe through the bed joint which is partially removed to allow for installation of the T-clip and the reinforcement wire. The exterior end of the helical wall tie and the reinforcement wire are set within the T-clip and secured therein with a mortar patch or sealant. A variation of the T-clip provides a corrugated portion to house the helical wall tie. The helical wall tie is spun into the corrugated portion. The present system is secure, economical and easy to install.
In addition to the patents set forth above, in preparing for this application the following patents and patent applications came to the attention of the inventors and are believed to be relevant to the further discussion of the prior art:
PatentInventorIssue Date4,473,984LopezOct. 2, 19844,631,889Adam et al.Dec. 30, 19864,772,166Shamah, et al.Sep. 20, 19884,875,319HohmannOct. 24, 19894,883,396Shamah et al.Nov. 28, 19895,644,889GetzJul. 8, 19977,404,274HayesJul. 29, 2008
FOREIGN PATENT DOCUMENTSPatentCountryFiling DateEP 0150906 A2GBJan. 4, 1985EP 0171250 A2GBJul. 29, 1985
U.S. Pat. No. 4,631,889—Adam, et al. —Issued Dec. 30, 1986 discloses a fixing device for use in cavity walls that employs a radially expandible ribbed sleeve element to lock a rod in a bore of a wall.
U.S. Pat. No. 4,473,984—Lopez—Issued Oct. 2, 1984 details a curtain-wall masonry-veneer anchor system that employs a threaded stud that is either coarsely threaded for self-tapping in predrilled masonry or self-drilling and self-tapping.
U.S. Pat. Nos. 4,772,166 and 4,883,396—Shamah, et al. —Issued Sep. 20, 1988 and Nov. 28, 1989, respectively disclose dual expansion and non-expansion anchors that are adjustable to the spaced positions of the inner and outer wythes. The inner non-expansion anchor is self-drilling and self-threading.
U.S. Pat. No. 5,644,889—Getz—Issued Jul. 8, 1997 provides a remedial wall anchor system that includes a tie rod, securing components and a capturing device. The capturing device is disclosed as being able to connect a reinforcement rod or wire. The Getz's device contains numerous component parts.
U.S. Pat. No. 4,875,319—Hohmann—Issued Oct. 24, 1989 describes a seismic construction system for use in a cavity wall. The seismic construction system includes a veneer anchor which is attached to the inner wythe, a tie member attached to the veneer anchor and a channeled seismic clip attached to the tie. The seismic clip houses a continuous reinforcing wire, which is embedded in the mortar joint of the veneer.
U.S. Pat. No. 7,404,274—Hayes—Issued Jul. 29, 2008 discloses a plastic anchoring device for reinforcing and renovating an existing masonry wall. The anchor is inserted into the wall and then filled with cement, forcing radial expansion.
None of the above references provide the advancements in restoration anchoring systems for cavity walls as set forth herein. The present novel three-part system offers an easy to use, cost effective and high strength solution to re-anchoring a damaged veneer. Through the use of the present novel restoration anchoring system for cavity walls, code requirements are met and construction costs are reduced.
The present invention provides an advancement in veneer re-anchoring and reinforcement by providing a restoration anchoring system for cavity walls that provides the same or better stability than the original embedded anchoring system. The present invention solves problems relating to seismic reinforcement and re-anchoring of the veneer by providing a three-part system that minimizes reconstruction of the veneer. The present anchoring system resolves past problems relating to re-anchoring, while simultaneously reducing installation, labor and energy costs, thereby saving time and money.
As will become clear in reviewing the disclosure which follows, the restoration anchoring system benefits from the recent developments described herein that leads to solving the problems of re-anchoring and reconstructing a cavity wall structure efficiently, from both a structural as well as a cost/time perspective.